Fire history investigations were carried out in three widely separated Great Basin pinyon-juniper woodlands in east-central Nevada, southeastern Oregon and northwestern Nevada, and western Nevada. Study results suggested frequent fires on deep soils that produced an abundance of fine fuels and infrequent fires on shallow soils and rocky sites where fuels were sparse. Decades of intensive livestock grazing and successful fire suppression in pinyon-juniper woodlands have resulted in a shift from low intensity fires to high intensity fires. This shift has been the result of large increases in woody fuels and introduction of exotic grasses. Considering the extent of fuel buildup, severe wildfires in the Great Basin will continue and perhaps become more frequent.